User blog comment:Sefiros2211/Dante's Age/@comment-134861-20130310194804/@comment-1164563-20140321171729

Not to undermine the reincarnation theory (I can't say i like it, personally, but it is more or less consistent, so I guess it gets a pass), I but remember a another theory where Alice, the girl from the manga, was supposed to seduce Vergil, probably while latter is under some kind of spell. Arkham's spell, that is. He was going to make sure that Sparda's blood is preserved, in case Dante and Vergil murder each other. One hell of a prank Jester pulled on Blue, indeed.

In case you are wondering, getting a backup of Lady's blood shouldn't be as much of a problem compared... the nameless priestess was a human that lived 2000 years ago, thus there is potentially a really large amount of direct descendants, while Sparda was supposed to have only two kids.